Device for forming square holes.



G; A. BROWN.

DEVICE FOR FORMING SQUARE HOLES. APPLICATION IILBD snrmzs, 1909.

Patented Apr. 26, 1910.

- a I A I nr ,IIIIIIIIIII C/zarZcs dfimzmz UNITED CHARLES A. BROWN, OFCONWAY, MISSOURI.

DEVICE FOR FORMING SQUARE HOLES.

Specification of Letters Patent.

Application filed September 28, 1909. Serial No. 519,959.

T0 (1 whom it only concern:

Be it known that I. CHARLES A. linown. a citizen of the United States,residing at tonway, in the county of Laclede and State of Missouri, haveinvented new and useful improvements in Devices for Forming SquareHoles, ot which the following is a. specificatlon.

This invention relates to devices for forming square holes, the objectof the invention being to provide. a combined auger and chisel in whichthe chisel is automatically reciprocated simultaneously with therotation of the boring bit whereby in forming the round or cylindricalhole, the chisel operates to chip out and remove portions of the woodaround the hole so that the resultant bore or hole is squared in crosssection.

A further object of the invention is to provide a construction whichwill admit of the several parts of the device being readily separatedand taken apart for sharpening and other repairs when necessary.

\Vith the above and other objects in view the invention consists in theuo\el construction. combination and arrangement of parts herein fullydescribed, illustrated and claimed.

In the accompanyin drawings :-Figure 1 is a longitudinal section partlyin elevation of the device of this invention. Fig. is a side elevationpartly in section taken at right angles to Fig. 1. Fig. 3 is a crosssection on the line 33 of Fig. 1. Fig. 4 is a face view of the boringbit.

Referring to the drawings 1 designates a boring bit and 2 the shankthereof, a shoulder 3 being formed at the junction of the boring portionof the bit and the shank 2. The boring bit is provided with the usualcutting portion 4 and centering point 5.

The boring bit and a portion of the shank thereof are embraced andinclosed by a casing comprising an upper section (5 and a lower section7, said sections being joined together by a threaded joint as shown at 8whereby they may be readily separated. The lower section 7 constitutes areciprocatory chisel which is square in cross section and the width ofwhich is equal to the diameter of the head or cutting portion 4- of theboring bit as indicated in Figs. 1 and Q. The lower extremity or edge ofthe chisel is sharpened as shown at 9 and each-side thereof is cut awayas shown at 10 to allow for the rotation of the cutting head 4, there- 1by leaving L-shaped corner cutting portions 11 which operate to cut awaythe wood at the places representing the four corners of a square hole.

To order to provide for automatically reciprocating the chisel 7, aratchet collar 12 is made fast on the shank 2 so as to rotate therewith.said collar having a single ratchet tooth 13 on its upper edge. Mountedloosely on theshank 2 is a cam sleeve 11 having its upper edge formed ona spiral and adapted to cooperate with a lug or tooth 16 on the innerface of the upper section 6 of the. casing as shown in Fig. 1. Thesleeve is also provided at its lower edge with a shoulder adapted toengage the shoulder or tooth 13 of the ratchet collar as shown in Fig. 1when the boring bit is turned to the right or in the boring direction.\Vhen the boring bit is reversed as in removing the same from the work,the shoulder of the cam sleeve rides over and snaps the tooth 13 of theratchet collar and in this backward or reverse movement of the boringbit, the usual reciprocatory movement is not imparted to the chisel.

The chisel is forced downward by means of an expansive coil spring 17which surrounds the shank 2 and is held between a collar 18 fastened tothe shank 2 by means of a set screw 19 and a loose collar 20 which bearsagainst the upper end of the casing 6. The set screw 19 provides foradjusting the. collar 18 and thereby the tension or thrust of the spring17.

In order to prevent the square casing from rotating during the rotationof the boring bit, I provide a square guide 21 through which the chiselis adapted to slide, said guide being provided at its lower end and thefour corners thereof with retainer points 22 which may be driven intothe wood sufficiently to enable the guide to be conveniently held in onehand of the operator while the other hand is used for turning the boringbit.

It will of course be understood that the boring bit may be operated bymeans of the usual brace or by a machine.

From the foregoing description it will be understood that as the boringbit is turned, the cam sleeve 14 acts to elevate the chisel and as soonas the edge 14 of the cam sleeve passes by the projection or tooth 16,the spring 17 which has been compressed, expands quickly and thrusts thechisel downlatentcd Apr. 26, 1910.

ward to its work, thereby chipping out such portions of the wood aroundthe hole formed by the boring bit as to produce a square hole. a

I claim 1. A device for forming square holes comprising a rotary boringbit, a hollow square chisel embracin the boring bit and mounted to slideup an down thereon comprising upper and lower sections detachablyconnected by a couplin joint, a cam on the shank of the boring it, aprojection within the upper portion of the casing with which said camcoo erates, and a spring having one end held by the shank of the boringbit and the other end operating against the upper section of the chiselcasing, substantially as described.

2. A device for forming square holes comprising a rotary borin bit, areciprocatory ch sel mounted to sli e lengthwise of the bit, and a camsleeve mounted loosely onthe shank of the bit, means on the shank of thebit for causin said cam sleeve to rotate therewith an permitting theboring bit to turn in a reverse direction without ro-- tating the camsleeve, means on the chisel CHARLES A. BROWN. Witnesses J. H. WILsoN, H.G. TAGGARD.

